Tiles have commonly been used to cover and protect interior walls from the effects of moisture. These tiles are usually square. U.S. Pat. Nos. 1,516,025;, 2,323,471; 2,693,102; and 3,444,660 concern square wall tiles that interlock.
To apply tiles to a wall surface, a worker applied an adhesive or mastic to the wall. The worker then applied each tile to the adhesive with spaces between adjacent tiles. The worker aligned the tiles horizontally and vertically for a neat appearance. However, it was very easy to apply the tiles in a crooked and unsightly manner. The worker usually applied grout in the spaces between each tile. Thus, a substantial amount of labor was involved in grouting and aligning these tiles.
U.S. Pat. No. 2,693,102 also describes tiles that have interlocking tabs and slots and indicates that grout joints are absent. However, it is difficult and costly to manufacture tiles with tabs and slots. Also, moisture can leak between and behind these tiles.
Oblong tiles have also been proposed. U.S. Pat. Nos. 347,425 and 2,323,417 concern tiles that may be oblong, for instance.
None of these tiles has a simple and effective device for aligning adjacent tiles and for draining moisture away from joints between adjacent tiles.